Figure 1: A reference anatomy (left) is automatically transferred to arbitrary humanoid characters. This is achieved by combining interpolated skin correspondences with anatomical rules. AbstractCharacters with precise internal anatomy are important in film and visual effects, as well as in medical applications. We propose the first semi-automatic method for creating anatomical structures, such as bones, muscles, viscera and fat tissues. This is done by transferring a reference anatomical model from an input template to an arbitrary target character, only defined by its boundary representation (skin). The fat distribution of the target character needs to be specified. We can either infer this information from MRI data, or allow the users to express their creative intent through a new editing tool. The rest of our method runs automatically: it first transfers the bones to the target character, while maintaining their structure as much as possible. The bone layer, along with the target skin eroded using the fat thickness information, are then used to define a volume where we map the internal anatomy of the source model using harmonic (Laplacian) deformation. This way, we are able to quickly generate anatomical models for a large range of target characters, while maintaining anatomical constraints.

International audienceThis paper presents a mirror-like augmented reality (AR) system to display the internal anatomy of the current user. Using a single Microsoft V2.0 Kinect (later on referenced as the Kinect), we animate in real-time a user-specific model of internal anatomy according to the user’s motion and we superimpose it onto the user’s color map. Userscan visualize their anatomy moving as if they where looking inside their own bodies in real-time.A new calibration procedure to set up and attach a user-specific anatomy to the Kinect body tracking skeleton is introduced. At calibration time, the bone lengths are estimated using a set of poses. By using Kinect data as input, the practical limitation of skin correspondence in prior work is overcome. The generic 3D anatomical model is attached to the internal anatomy registration skeleton, and warped on the depth image using a novel elastic deformer subject to a closest-point registration force and anatomical constraints. The noise in Kinect outputs precludes direct display of realistic human anatomy. Therefore, to enforce anatomical plausibility, a novel filter to reconstruct plausiblemotions based on fixed bones lengths as well as realistic angular degrees of freedom DOFs) and limits are introduced. Anatomical constraints, applied to the Kinect body tracking skeleton joints, are used to maximize the physical plausibility of the anatomy motion while minimizing the distance to the raw data. At run-time, a simulation loop is used to attract the bones towards the raw data. Skinning shaders efficiently drag the resulting anatomy to the user’s tracked motion. Our user-specific internal anatomy model is validated by comparing the skeleton withsegmented MRI images. A user study is established to evaluate the believability of the animated anatomy.As an extension of Bauer et al. (2016), we also propose an image-based algorithm that corrects accumulated inaccuracy of the system steps: motion capture, anatomy transfer, image generation and animation. These inaccuracies show up as occlusion and self-occlusion misalignments of the anatomy regions when superimposed between them and on top of the color map. We also show that the proposed work can efficiently reduce these inaccuracies